1. Field of the Invention
This invention relates to a novel process for preparing an aromatic urethane compound. More particularly, it relates to a process for preparing an aromatic urethane from an aromatic primary amino compound having a nitro group, a nitroso group or a carbamate group, an organic compound containing at least one hydroxyl group, and carbon monoxide.
2. Description of the Prior Art
There have been recently proposed a large number of processes for producing aromatic urethanes from aromatic nitro compounds, organic compounds containing at least one hydroxyl group (hereinlater referred to simply as hydroxyl group-containing compound), and carbon monoxide in the presence of catalysts.
For example, U.S. Pat. No. 3,338,956 describes a process using rhodium chlorocarbonyl as a catalyst for the urethanation reaction. Further, British Pat. No. 1,543,051 discloses a process with which the urethanation reaction is conducted in rhodium chlorocarbonyl as the catalyst and a multi-valent metal halide as the promoter. In these processes, however, aromatic nitro compounds are essentially used as a principal starting material to permit the nitro group or groups to take part in the urethanation reaction.
As a result of an extensive study of a process of producing aromatic urethanes, we have found a hitherto unknown, really novel process for producing aromatic urethanes in which the urethanes can be produced from aromatic primary amine compounds, carbon monoxide and hydroxyl group-containing compounds.